As double iron planes, my Clifton’s have a chip breaker that is engineering perfection, right where it counts. Yes the blade is a bit thicker and the plane heavy.
Some thoughts on thicker plane irons:

When irons are thicker than ~1/8" they can be a pain to sharpen for us members of the flat bevel society.

Being thicker adds weight to the iron. Extra weight requires more energy to set up resonance in the blade. Resonance is one aspect of chatter. Part of the idea of a chip breaker/ cap iron was to help prevent chatter with thin irons. Good plane design will also help to lessen chatter.

jtk